Rotate the map so your path goes from left to right – that helps match up events in the graphs with their location on the map. The screen shot to the right shows the bridge and intersection that caused the spikes in IRI.
Get the start and end markers close to where you want them and then zoom in on the map and change to the satellite view to place them precisely.
If you don’t have a network or cell connection, you can still review the results. You can have a detailed map without a network connection if you use the “Save offline map” feature in Google Maps.
Start RoadBump while your vehicle is at rest
Come to a full stop before ending the recording
Set a minimum speed so you don’t have to start or stop RoadBump while driving
Record at least a few seconds before and after the path you are measuring – you can easily set the start and end markers and save the smaller path later
Record long paths in 1 run and later save smaller sections as individual recordings
Best results are around 40 to 60 mph
Calculations are done based on testing on tracks with known at speeds between 30 and 60 mph. The estimated IRI results from speeds outside this range are projected from the test data.
Use cruise control where practical
Accelerate and brake smoothly
Drive the same path multiple times, focus on consistent lane positioning
Recordings over 1 hour in length are more difficult to manipulate.
Flat spot on a non-slip pad on the dashboard
Non-slip pad on center console
Windshield mount (the steadier the better)
Floor (keep from sliding)
Cup holder (keep from moving)
Seat (keep from bouncing)
Hand (last resort)
Device Placement - from Best to Worst
Put your device in Airplane mode to avoid time differences between cell towers, interruptions and to save battery life